<?php

// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]
// +----------------------------------------------------------------------
// | Copyright (c) 2009 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

namespace Think\Crypt\Driver;

/**
 * Des 加密实现类
 * Converted from JavaScript to PHP by Jim Gibbs, June 2004 Paul Tero, July 2001
 * Optimised for performance with large blocks by Michael Hayworth, November 2001
 * http://www.netdealing.com
 */
class Des {

    /**
     * 加密字符串
     * @param string $str 字符串
     * @param string $key 加密key
     * @param integer $expire 有效期（秒）     
     * @return string
     */
    public static function encrypt($str, $key, $expire = 0) {
        if ($str == "") {
            return "";
        }
        $expire = sprintf('%010d', $expire ? $expire + time() : 0);
        $str = $expire . $str;
        return self::_des($key, $str, 1);
    }

    /**
     * 解密字符串
     * @param string $str 字符串
     * @param string $key 加密key
     * @return string
     */
    public static function decrypt($str, $key) {
        if ($str == "") {
            return "";
        }
        $data = self::_des($key, $str, 0);
        $expire = substr($data, 0, 10);
        if ($expire > 0 && $expire < time()) {
            return '';
        }
        $data = substr($data, 10);
        return $data;
    }

    /**
     * Des算法
     * @param string $str 字符串
     * @param string $key 加密key
     * @return string
     */
    private static function _des($key, $message, $encrypt, $mode = 0, $iv = null) {
        //declaring this locally speeds things up a bit
        $spfunction1 = array(0x1010400, 0, 0x10000, 0x1010404, 0x1010004, 0x10404, 0x4, 0x10000, 0x400, 0x1010400, 0x1010404, 0x400, 0x1000404, 0x1010004, 0x1000000, 0x4, 0x404, 0x1000400, 0x1000400, 0x10400, 0x10400, 0x1010000, 0x1010000, 0x1000404, 0x10004, 0x1000004, 0x1000004, 0x10004, 0, 0x404, 0x10404, 0x1000000, 0x10000, 0x1010404, 0x4, 0x1010000, 0x1010400, 0x1000000, 0x1000000, 0x400, 0x1010004, 0x10000, 0x10400, 0x1000004, 0x400, 0x4, 0x1000404, 0x10404, 0x1010404, 0x10004, 0x1010000, 0x1000404, 0x1000004, 0x404, 0x10404, 0x1010400, 0x404, 0x1000400, 0x1000400, 0, 0x10004, 0x10400, 0, 0x1010004);
        $spfunction2 = array(-0x7fef7fe0, -0x7fff8000, 0x8000, 0x108020, 0x100000, 0x20, -0x7fefffe0, -0x7fff7fe0, -0x7fffffe0, -0x7fef7fe0, -0x7fef8000, -0x80000000, -0x7fff8000, 0x100000, 0x20, -0x7fefffe0, 0x108000, 0x100020, -0x7fff7fe0, 0, -0x80000000, 0x8000, 0x108020, -0x7ff00000, 0x100020, -0x7fffffe0, 0, 0x108000, 0x8020, -0x7fef8000, -0x7ff00000, 0x8020, 0, 0x108020, -0x7fefffe0, 0x100000, -0x7fff7fe0, -0x7ff00000, -0x7fef8000, 0x8000, -0x7ff00000, -0x7fff8000, 0x20, -0x7fef7fe0, 0x108020, 0x20, 0x8000, -0x80000000, 0x8020, -0x7fef8000, 0x100000, -0x7fffffe0, 0x100020, -0x7fff7fe0, -0x7fffffe0, 0x100020, 0x108000, 0, -0x7fff8000, 0x8020, -0x80000000, -0x7fefffe0, -0x7fef7fe0, 0x108000);
        $spfunction3 = array(0x208, 0x8020200, 0, 0x8020008, 0x8000200, 0, 0x20208, 0x8000200, 0x20008, 0x8000008, 0x8000008, 0x20000, 0x8020208, 0x20008, 0x8020000, 0x208, 0x8000000, 0x8, 0x8020200, 0x200, 0x20200, 0x8020000, 0x8020008, 0x20208, 0x8000208, 0x20200, 0x20000, 0x8000208, 0x8, 0x8020208, 0x200, 0x8000000, 0x8020200, 0x8000000, 0x20008, 0x208, 0x20000, 0x8020200, 0x8000200, 0, 0x200, 0x20008, 0x8020208, 0x8000200, 0x8000008, 0x200, 0, 0x8020008, 0x8000208, 0x20000, 0x8000000, 0x8020208, 0x8, 0x20208, 0x20200, 0x8000008, 0x8020000, 0x8000208, 0x208, 0x8020000, 0x20208, 0x8, 0x8020008, 0x20200);
        $spfunction4 = array(0x802001, 0x2081, 0x2081, 0x80, 0x802080, 0x800081, 0x800001, 0x2001, 0, 0x802000, 0x802000, 0x802081, 0x81, 0, 0x800080, 0x800001, 0x1, 0x2000, 0x800000, 0x802001, 0x80, 0x800000, 0x2001, 0x2080, 0x800081, 0x1, 0x2080, 0x800080, 0x2000, 0x802080, 0x802081, 0x81, 0x800080, 0x800001, 0x802000, 0x802081, 0x81, 0, 0, 0x802000, 0x2080, 0x800080, 0x800081, 0x1, 0x802001, 0x2081, 0x2081, 0x80, 0x802081, 0x81, 0x1, 0x2000, 0x800001, 0x2001, 0x802080, 0x800081, 0x2001, 0x2080, 0x800000, 0x802001, 0x80, 0x800000, 0x2000, 0x802080);
        $spfunction5 = array(0x100, 0x2080100, 0x2080000, 0x42000100, 0x80000, 0x100, 0x40000000, 0x2080000, 0x40080100, 0x80000, 0x2000100, 0x40080100, 0x42000100, 0x42080000, 0x80100, 0x40000000, 0x2000000, 0x40080000, 0x40080000, 0, 0x40000100, 0x42080100, 0x42080100, 0x2000100, 0x42080000, 0x40000100, 0, 0x42000000, 0x2080100, 0x2000000, 0x42000000, 0x80100, 0x80000, 0x42000100, 0x100, 0x2000000, 0x40000000, 0x2080000, 0x42000100, 0x40080100, 0x2000100, 0x40000000, 0x42080000, 0x2080100, 0x40080100, 0x100, 0x2000000, 0x42080000, 0x42080100, 0x80100, 0x42000000, 0x42080100, 0x2080000, 0, 0x40080000, 0x42000000, 0x80100, 0x2000100, 0x40000100, 0x80000, 0, 0x40080000, 0x2080100, 0x40000100);
        $spfunction6 = array(0x20000010, 0x20400000, 0x4000, 0x20404010, 0x20400000, 0x10, 0x20404010, 0x400000, 0x20004000, 0x404010, 0x400000, 0x20000010, 0x400010, 0x20004000, 0x20000000, 0x4010, 0, 0x400010, 0x20004010, 0x4000, 0x404000, 0x20004010, 0x10, 0x20400010, 0x20400010, 0, 0x404010, 0x20404000, 0x4010, 0x404000, 0x20404000, 0x20000000, 0x20004000, 0x10, 0x20400010, 0x404000, 0x20404010, 0x400000, 0x4010, 0x20000010, 0x400000, 0x20004000, 0x20000000, 0x4010, 0x20000010, 0x20404010, 0x404000, 0x20400000, 0x404010, 0x20404000, 0, 0x20400010, 0x10, 0x4000, 0x20400000, 0x404010, 0x4000, 0x400010, 0x20004010, 0, 0x20404000, 0x20000000, 0x400010, 0x20004010);
        $spfunction7 = array(0x200000, 0x4200002, 0x4000802, 0, 0x800, 0x4000802, 0x200802, 0x4200800, 0x4200802, 0x200000, 0, 0x4000002, 0x2, 0x4000000, 0x4200002, 0x802, 0x4000800, 0x200802, 0x200002, 0x4000800, 0x4000002, 0x4200000, 0x4200800, 0x200002, 0x4200000, 0x800, 0x802, 0x4200802, 0x200800, 0x2, 0x4000000, 0x200800, 0x4000000, 0x200800, 0x200000, 0x4000802, 0x4000802, 0x4200002, 0x4200002, 0x2, 0x200002, 0x4000000, 0x4000800, 0x200000, 0x4200800, 0x802, 0x200802, 0x4200800, 0x802, 0x4000002, 0x4200802, 0x4200000, 0x200800, 0, 0x2, 0x4200802, 0, 0x200802, 0x4200000, 0x800, 0x4000002, 0x4000800, 0x800, 0x200002);
        $spfunction8 = array(0x10001040, 0x1000, 0x40000, 0x10041040, 0x10000000, 0x10001040, 0x40, 0x10000000, 0x40040, 0x10040000, 0x10041040, 0x41000, 0x10041000, 0x41040, 0x1000, 0x40, 0x10040000, 0x10000040, 0x10001000, 0x1040, 0x41000, 0x40040, 0x10040040, 0x10041000, 0x1040, 0, 0, 0x10040040, 0x10000040, 0x10001000, 0x41040, 0x40000, 0x41040, 0x40000, 0x10041000, 0x1000, 0x40, 0x10040040, 0x1000, 0x41040, 0x10001000, 0x40, 0x10000040, 0x10040000, 0x10040040, 0x10000000, 0x40000, 0x10001040, 0, 0x10041040, 0x40040, 0x10000040, 0x10040000, 0x10001000, 0x10001040, 0, 0x10041040, 0x41000, 0x41000, 0x1040, 0x1040, 0x40040, 0x10000000, 0x10041000);
        $masks = array(4294967295, 2147483647, 1073741823, 536870911, 268435455, 134217727, 67108863, 33554431, 16777215, 8388607, 4194303, 2097151, 1048575, 524287, 262143, 131071, 65535, 32767, 16383, 8191, 4095, 2047, 1023, 511, 255, 127, 63, 31, 15, 7, 3, 1, 0);

        //create the 16 or 48 subkeys we will need
        $keys = self::_createKeys($key);
        $m = 0;
        $len = strlen($message);
        $chunk = 0;
        //set up the loops for single and triple des
        $iterations = ((count($keys) == 32) ? 3 : 9); //single or triple des
        if ($iterations == 3) {
            $looping = (($encrypt) ? array(0, 32, 2) : array(30, -2, -2));
        } else {
            $looping = (($encrypt) ? array(0, 32, 2, 62, 30, -2, 64, 96, 2) : array(94, 62, -2, 32, 64, 2, 30, -2, -2));
        }

        $message .= (chr(0) . chr(0) . chr(0) . chr(0) . chr(0) . chr(0) . chr(0) . chr(0)); //pad the message out with null bytes
        //store the result here
        $result = "";
        $tempresult = "";

        if ($mode == 1) { //CBC mode
            $cbcleft = (ord($iv{$m++}) << 24) | (ord($iv{$m++}) << 16) | (ord($iv{$m++}) << 8) | ord($iv{$m++});
            $cbcright = (ord($iv{$m++}) << 24) | (ord($iv{$m++}) << 16) | (ord($iv{$m++}) << 8) | ord($iv{$m++});
            $m = 0;
        }

        //loop through each 64 bit chunk of the message
        while ($m < $len) {
            $left = (ord($message{$m++}) << 24) | (ord($message{$m++}) << 16) | (ord($message{$m++}) << 8) | ord($message{$m++});
            $right = (ord($message{$m++}) << 24) | (ord($message{$m++}) << 16) | (ord($message{$m++}) << 8) | ord($message{$m++});

            //for Cipher Block Chaining mode, xor the message with the previous result
            if ($mode == 1) {
                if ($encrypt) {
                    $left ^= $cbcleft;
                    $right ^= $cbcright;
                } else {
                    $cbcleft2 = $cbcleft;
                    $cbcright2 = $cbcright;
                    $cbcleft = $left;
                    $cbcright = $right;
                }
            }

            //first each 64 but chunk of the message must be permuted according to IP
            $temp = (($left >> 4 & $masks[4]) ^ $right) & 0x0f0f0f0f;
            $right ^= $temp;
            $left ^= ($temp << 4);
            $temp = (($left >> 16 & $masks[16]) ^ $right) & 0x0000ffff;
            $right ^= $temp;
            $left ^= ($temp << 16);
            $temp = (($right >> 2 & $masks[2]) ^ $left) & 0x33333333;
            $left ^= $temp;
            $right ^= ($temp << 2);
            $temp = (($right >> 8 & $masks[8]) ^ $left) & 0x00ff00ff;
            $left ^= $temp;
            $right ^= ($temp << 8);
            $temp = (($left >> 1 & $masks[1]) ^ $right) & 0x55555555;
            $right ^= $temp;
            $left ^= ($temp << 1);

            $left = (($left << 1) | ($left >> 31 & $masks[31]));
            $right = (($right << 1) | ($right >> 31 & $masks[31]));

            //do this either 1 or 3 times for each chunk of the message
            for ($j = 0; $j < $iterations; $j+=3) {
                $endloop = $looping[$j + 1];
                $loopinc = $looping[$j + 2];
                //now go through and perform the encryption or decryption
                for ($i = $looping[$j]; $i != $endloop; $i+=$loopinc) { //for efficiency
                    $right1 = $right ^ $keys[$i];
                    $right2 = (($right >> 4 & $masks[4]) | ($right << 28)) ^ $keys[$i + 1];
                    //the result is attained by passing these bytes through the S selection functions
                    $temp = $left;
                    $left = $right;
                    $right = $temp ^ ($spfunction2[($right1 >> 24 & $masks[24]) & 0x3f] | $spfunction4[($right1 >> 16 & $masks[16]) & 0x3f] | $spfunction6[($right1 >> 8 & $masks[8]) & 0x3f] | $spfunction8[$right1 & 0x3f] | $spfunction1[($right2 >> 24 & $masks[24]) & 0x3f] | $spfunction3[($right2 >> 16 & $masks[16]) & 0x3f] | $spfunction5[($right2 >> 8 & $masks[8]) & 0x3f] | $spfunction7[$right2 & 0x3f]);
                }
                $temp = $left;
                $left = $right;
                $right = $temp; //unreverse left and right
            } //for either 1 or 3 iterations
            //move then each one bit to the right
            $left = (($left >> 1 & $masks[1]) | ($left << 31));
            $right = (($right >> 1 & $masks[1]) | ($right << 31));

            //now perform IP-1, which is IP in the opposite direction
            $temp = (($left >> 1 & $masks[1]) ^ $right) & 0x55555555;
            $right ^= $temp;
            $left ^= ($temp << 1);
            $temp = (($right >> 8 & $masks[8]) ^ $left) & 0x00ff00ff;
            $left ^= $temp;
            $right ^= ($temp << 8);
            $temp = (($right >> 2 & $masks[2]) ^ $left) & 0x33333333;
            $left ^= $temp;
            $right ^= ($temp << 2);
            $temp = (($left >> 16 & $masks[16]) ^ $right) & 0x0000ffff;
            $right ^= $temp;
            $left ^= ($temp << 16);
            $temp = (($left >> 4 & $masks[4]) ^ $right) & 0x0f0f0f0f;
            $right ^= $temp;
            $left ^= ($temp << 4);

            //for Cipher Block Chaining mode, xor the message with the previous result
            if ($mode == 1) {
                if ($encrypt) {
                    $cbcleft = $left;
                    $cbcright = $right;
                } else {
                    $left ^= $cbcleft2;
                    $right ^= $cbcright2;
                }
            }
            $tempresult .= (chr($left >> 24 & $masks[24]) . chr(($left >> 16 & $masks[16]) & 0xff) . chr(($left >> 8 & $masks[8]) & 0xff) . chr($left & 0xff) . chr($right >> 24 & $masks[24]) . chr(($right >> 16 & $masks[16]) & 0xff) . chr(($right >> 8 & $masks[8]) & 0xff) . chr($right & 0xff));

            $chunk += 8;
            if ($chunk == 512) {
                $result .= $tempresult;
                $tempresult = "";
                $chunk = 0;
            }
        } //for every 8 characters, or 64 bits in the message
        //return the result as an array
        return ($result . $tempresult);
    }

//end of des

    /**
     * createKeys
     * this takes as input a 64 bit key (even though only 56 bits are used)
     * as an array of 2 integers, and returns 16 48 bit keys
     * @param string $key 加密key
     * @return string
     */
    private static function _createKeys($key) {
        //declaring this locally speeds things up a bit
        $pc2bytes0 = array(0, 0x4, 0x20000000, 0x20000004, 0x10000, 0x10004, 0x20010000, 0x20010004, 0x200, 0x204, 0x20000200, 0x20000204, 0x10200, 0x10204, 0x20010200, 0x20010204);
        $pc2bytes1 = array(0, 0x1, 0x100000, 0x100001, 0x4000000, 0x4000001, 0x4100000, 0x4100001, 0x100, 0x101, 0x100100, 0x100101, 0x4000100, 0x4000101, 0x4100100, 0x4100101);
        $pc2bytes2 = array(0, 0x8, 0x800, 0x808, 0x1000000, 0x1000008, 0x1000800, 0x1000808, 0, 0x8, 0x800, 0x808, 0x1000000, 0x1000008, 0x1000800, 0x1000808);
        $pc2bytes3 = array(0, 0x200000, 0x8000000, 0x8200000, 0x2000, 0x202000, 0x8002000, 0x8202000, 0x20000, 0x220000, 0x8020000, 0x8220000, 0x22000, 0x222000, 0x8022000, 0x8222000);
        $pc2bytes4 = array(0, 0x40000, 0x10, 0x40010, 0, 0x40000, 0x10, 0x40010, 0x1000, 0x41000, 0x1010, 0x41010, 0x1000, 0x41000, 0x1010, 0x41010);
        $pc2bytes5 = array(0, 0x400, 0x20, 0x420, 0, 0x400, 0x20, 0x420, 0x2000000, 0x2000400, 0x2000020, 0x2000420, 0x2000000, 0x2000400, 0x2000020, 0x2000420);
        $pc2bytes6 = array(0, 0x10000000, 0x80000, 0x10080000, 0x2, 0x10000002, 0x80002, 0x10080002, 0, 0x10000000, 0x80000, 0x10080000, 0x2, 0x10000002, 0x80002, 0x10080002);
        $pc2bytes7 = array(0, 0x10000, 0x800, 0x10800, 0x20000000, 0x20010000, 0x20000800, 0x20010800, 0x20000, 0x30000, 0x20800, 0x30800, 0x20020000, 0x20030000, 0x20020800, 0x20030800);
        $pc2bytes8 = array(0, 0x40000, 0, 0x40000, 0x2, 0x40002, 0x2, 0x40002, 0x2000000, 0x2040000, 0x2000000, 0x2040000, 0x2000002, 0x2040002, 0x2000002, 0x2040002);
        $pc2bytes9 = array(0, 0x10000000, 0x8, 0x10000008, 0, 0x10000000, 0x8, 0x10000008, 0x400, 0x10000400, 0x408, 0x10000408, 0x400, 0x10000400, 0x408, 0x10000408);
        $pc2bytes10 = array(0, 0x20, 0, 0x20, 0x100000, 0x100020, 0x100000, 0x100020, 0x2000, 0x2020, 0x2000, 0x2020, 0x102000, 0x102020, 0x102000, 0x102020);
        $pc2bytes11 = array(0, 0x1000000, 0x200, 0x1000200, 0x200000, 0x1200000, 0x200200, 0x1200200, 0x4000000, 0x5000000, 0x4000200, 0x5000200, 0x4200000, 0x5200000, 0x4200200, 0x5200200);
        $pc2bytes12 = array(0, 0x1000, 0x8000000, 0x8001000, 0x80000, 0x81000, 0x8080000, 0x8081000, 0x10, 0x1010, 0x8000010, 0x8001010, 0x80010, 0x81010, 0x8080010, 0x8081010);
        $pc2bytes13 = array(0, 0x4, 0x100, 0x104, 0, 0x4, 0x100, 0x104, 0x1, 0x5, 0x101, 0x105, 0x1, 0x5, 0x101, 0x105);
        $masks = array(4294967295, 2147483647, 1073741823, 536870911, 268435455, 134217727, 67108863, 33554431, 16777215, 8388607, 4194303, 2097151, 1048575, 524287, 262143, 131071, 65535, 32767, 16383, 8191, 4095, 2047, 1023, 511, 255, 127, 63, 31, 15, 7, 3, 1, 0);

        //how many iterations (1 for des, 3 for triple des)
        $iterations = ((strlen($key) >= 24) ? 3 : 1);
        //stores the return keys
        $keys = array(); // size = 32 * iterations but you don't specify this in php
        //now define the left shifts which need to be done
        $shifts = array(0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0);
        //other variables
        $m = 0;
        $n = 0;

        for ($j = 0; $j < $iterations; $j++) { //either 1 or 3 iterations
            $left = (ord($key{$m++}) << 24) | (ord($key{$m++}) << 16) | (ord($key{$m++}) << 8) | ord($key{$m++});
            $right = (ord($key{$m++}) << 24) | (ord($key{$m++}) << 16) | (ord($key{$m++}) << 8) | ord($key{$m++});

            $temp = (($left >> 4 & $masks[4]) ^ $right) & 0x0f0f0f0f;
            $right ^= $temp;
            $left ^= ($temp << 4);
            $temp = (($right >> 16 & $masks[16]) ^ $left) & 0x0000ffff;
            $left ^= $temp;
            $right ^= ($temp << -16);
            $temp = (($left >> 2 & $masks[2]) ^ $right) & 0x33333333;
            $right ^= $temp;
            $left ^= ($temp << 2);
            $temp = (($right >> 16 & $masks[16]) ^ $left) & 0x0000ffff;
            $left ^= $temp;
            $right ^= ($temp << -16);
            $temp = (($left >> 1 & $masks[1]) ^ $right) & 0x55555555;
            $right ^= $temp;
            $left ^= ($temp << 1);
            $temp = (($right >> 8 & $masks[8]) ^ $left) & 0x00ff00ff;
            $left ^= $temp;
            $right ^= ($temp << 8);
            $temp = (($left >> 1 & $masks[1]) ^ $right) & 0x55555555;
            $right ^= $temp;
            $left ^= ($temp << 1);

            //the right side needs to be shifted and to get the last four bits of the left side
            $temp = ($left << 8) | (($right >> 20 & $masks[20]) & 0x000000f0);
            //left needs to be put upside down
            $left = ($right << 24) | (($right << 8) & 0xff0000) | (($right >> 8 & $masks[8]) & 0xff00) | (($right >> 24 & $masks[24]) & 0xf0);
            $right = $temp;

            //now go through and perform these shifts on the left and right keys
            for ($i = 0; $i < count($shifts); $i++) {
                //shift the keys either one or two bits to the left
                if ($shifts[$i] > 0) {
                    $left = (($left << 2) | ($left >> 26 & $masks[26]));
                    $right = (($right << 2) | ($right >> 26 & $masks[26]));
                } else {
                    $left = (($left << 1) | ($left >> 27 & $masks[27]));
                    $right = (($right << 1) | ($right >> 27 & $masks[27]));
                }
                $left = $left & -0xf;
                $right = $right & -0xf;

                //now apply PC-2, in such a way that E is easier when encrypting or decrypting
                //this conversion will look like PC-2 except only the last 6 bits of each byte are used
                //rather than 48 consecutive bits and the order of lines will be according to
                //how the S selection functions will be applied: S2, S4, S6, S8, S1, S3, S5, S7
                $lefttemp = $pc2bytes0[$left >> 28 & $masks[28]] | $pc2bytes1[($left >> 24 & $masks[24]) & 0xf] | $pc2bytes2[($left >> 20 & $masks[20]) & 0xf] | $pc2bytes3[($left >> 16 & $masks[16]) & 0xf] | $pc2bytes4[($left >> 12 & $masks[12]) & 0xf] | $pc2bytes5[($left >> 8 & $masks[8]) & 0xf] | $pc2bytes6[($left >> 4 & $masks[4]) & 0xf];
                $righttemp = $pc2bytes7[$right >> 28 & $masks[28]] | $pc2bytes8[($right >> 24 & $masks[24]) & 0xf] | $pc2bytes9[($right >> 20 & $masks[20]) & 0xf] | $pc2bytes10[($right >> 16 & $masks[16]) & 0xf] | $pc2bytes11[($right >> 12 & $masks[12]) & 0xf] | $pc2bytes12[($right >> 8 & $masks[8]) & 0xf] | $pc2bytes13[($right >> 4 & $masks[4]) & 0xf];
                $temp = (($righttemp >> 16 & $masks[16]) ^ $lefttemp) & 0x0000ffff;
                $keys[$n++] = $lefttemp ^ $temp;
                $keys[$n++] = $righttemp ^ ($temp << 16);
            }
        } //for each iterations
        //return the keys we've created
        return $keys;
    }

//end of des_createKeys
}
